1. Field of the Invention
The present invention relates to the auditing of databases and, more particularly, to the auditing of large databases with varied record formats such as those used in enhanced 911 emergency telephone services.
2. Description of the Prior Art
Many corporations and government agencies work with databases composed of millions of records. Errors can be introduced into these records through software defects, electromagnetic interference with the storage media, or through human oversight when entering or modifying data. In many applications, errors are discovered and corrected during the regular course of business, such as when a bank statement is reconciled monthly. However, where a record is not regularly accessed or updated, an error can lie undetected for years.
A database containing important information should be periodically audited to verify its integrity, particularly when the database has records that are not regularly accessed or updated. Although intuition favors the idea of periodic audits, economic or logistic obstacles often frustrate this practice. The task becomes even more daunting when an audit involves reconciling several different databases containing related information in different formats, or when the databases are located remotely from one another. Also, some databases are not readily available for audit because they are subject to some level of regular activity.
Enhanced 911 (E911) telephone service allows a person to call for emergency assistance by dialing 911 from a telephone. An E911 call is routed to an E911 switchboard. An operator at the E911 switchboard speaks with the caller and views information on a display.
An E911 call is typically rout ed to an E911 switchboard in a firehouse or police department that services the area from which the call originated. The routing of the E911 call is determined by an emergency service number (ESN) stored in an E911 selective router database (SRDB) associated with a tandem switch (hereinafter "tandem"). A tandem routes a telephone call from its point of initiation to a destination. A typical SRDB contains records relating to 200,000 to 1,000,000 telephone numbers. An error in an SRDB can misdirect an E911 call, and delay the response to the emergency. The consequence of such a delay could, most certainly be very serious or grave.
Throughout the northeast United States, there are dozens of SRDB's containing records for tens of millions of telephone numbers. Tandems are manufactured by several different vendors, and the record formats for data stored in the SRDB's are not standardized. An SRDB record is updated in the normal course of business, only when a telephone line is initially activated or when the customer changes address but keeps the same telephone number. Since most telephone lines, once activated, remain so for years, an error in an SRDB record is not likely to be discovered.